Depletion of metal in the rat hippocampal mossy fibre system by intravital chelation with dithizone.
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Animals↗
Biomedical subjects
G Danscher
Publications and source records attributed to G Danscher.
Differentiation of histochemically visualized mercury and silver.
Accumulations of silver and mercury can be visualized in tissue sections by a technique called autometallography or physical development. In order to make a histological differentiation between mercury and silver in tissue exposed to both metals, it is necessary to remove one of the metals while leaving the other untouched. The present paper describes a technique by which silver accumulations in histological sections can be removed by potassium cyanide, yet leaving mercury accumulations intact to be developed autometallographically.
Animals↗
Histochemical tracing of bismuth in testis from rats exposed intraperitoneally to bismuth subnitrate.
The histochemical silver amplification technique autometallography (AMG), was used to trace bismuth in the testis of Wistar rats injected intraperitoneally with bismuth subnitrate. In the seminiferous tubules, bismuth was located in lysosomes of Sertoli cells closely associated with heads of spermatids in the late stages of the spermatogenesis, i.e. shortly before the release of Step 19 spermatids in Stage XIII. No bismuth-specific AMG silver grains were detected in the spermatogenic cell line. However, tails of free sperm cells located in the tubular lumen showed autometallographic grains in close contact to the nine outer microtubule doublets in the axonema. Leydig cells concentrated huge amounts of AMG-bismuth in their lysosomes. Furthermore, parallel exposure to selenium significantly increased the amount of histochemically traceable bismuth in the rat testis.
Animals↗
Uptake of bismuth in motor neurons of mice after single oral doses of bismuth compounds.
Bismuth, a component of many gastrointestinal medications, is a heavy metal little studied as regards nervous system uptake. We were interested to see if low doses of intragastric bismuth entered the nervous system, and if dietary selenium influenced the amount of bismuth detected. Mice were given 40 to 1200 mg/kg of bismuth subnitrate (BSN), bismuth subsalicylate (BSS), colloidal bismuth subcitrate (CBS), or ranitidine bismuth citrate (RBC) intragastrically. Mice on low- or high-selenium diets were given 4 to 32 mg/kg of bismuth from RBC. One week later, sections of nervous tissue were stained with autometallography to detect bismuth grains (Bi(AMG)). Bismuth was found in neurons with axons outside of the nervous system, in particular motor neurons, and in cells outside the blood-brain barrier. The lowest bismuth dose which resulted in Bi(AMG) in motor neurons was 696 mg/kg from BSN, 57 mg/kg from BSS, 29 mg/kg from CBS, and 26 mg/kg from RBC. No bismuth was seen in motor neurons of mice on the low-selenium diet. Intragastric doses of bismuth therefore enter mouse motor neurons, and the amount detectable varies with dietary selenium.
Administration, Oral↗
PC-assisted three-dimensional description of organs containing tubular structures, applied on the epididymis of the rat.
A concept for three-dimensional computer-assisted reconstruction of tubular organs, e.g. the epididymis, is described. Histologic serial sections without artificial landmarks from the epididymis of the Wistar rat were aligned. Virtual images through the aligned sections served as a control of the alignment process and can reveal new information about the structure of the organ under investigation. The method can be used for improving the anatomical description of the epididymis, i.e. how the ductus epididymidis is coiled along this organ. Other tubular tissues and organs can be investigated and analysed with this PC-assisted method, e.g. testis and kidney.
Algorithms↗
Organic mercury: an environmental threat to the health of dietary-exposed societies?
As a natural element, mercury is ubiquitous in the environment. The largest amount of mercury, amounting to approximately 100,000 tons per year, originates from the degassing of the earth's crust. To this amount, such anthropogenic activities as combustion of fossil fuels and releases from industrial activities add approximately 20,000 tons of mercury every year. The emitted mercury, both natural and anthropogenic, is in an inorganic form, predominantly as the metallic vapor (Hgzero). In aquatic environments, however, inorganic mercury is microbiologically transformed into the lipophilic organic compound, methylmercury. The transformation from the hydrophilic to the lipophilic state makes mercury more prone to biomagnification in aquatic food chains. Consequently, populations with a traditionally high dietary intake of food originating from either fresh-water or marine environments have the highest exposure to methylmercury. Because of their traditional pursuit of marine mammals, the Inuits belong to the highest dietary exposure group /1/. This situation is particularly true for the Polar Eskimos in North West Greenland. This population has the most traditional lifestyle among the Inuits and hunts predatory species of whales, such as beluga and narwhal, a combination that results in a high level of exposure to methylmercury. Polar Eskimos in North West Greenland, living in areas with no 'accidental' mercury pollution, but with a high dietary access to methylmercury thus exemplify a population group with a current potential environmental health problem.
Carcinogens, Environmental↗
Autometallographic demonstration of gold in rheumatoid synovial tissue.
A new autometallographic method for the detection of gold was applied to synovial tissue obtained by synovectomy from 30 patients with chronic arthritis. Granules staining for gold were visualized in biopsies from 26 patients previously or currently treated with gold, but not in biopsies from untreated patients. Location of macrophages was confirmed, and in half the biopsies fibroblast-like cells were also stained. Lymphocytes, plasma cells and interstitial tissue were devoid of gold. Granules were seen after treatment with as small an amount as 85 mg gold sodium aurothiomalate. The amount of gold staining varied between the biopsies and seemed to be related to the amount of gold given. Within individual biopsies, the distribution of gold staining was irregular. It is suggested that there may be at least two targets of chrysotherapy in arthritic joints, and that an influence of gold on the immune system may take place, at least in part, via the macrophages. A relationship between the biopsy findings and the clinical course could not be established.
Adolescent↗